Apparatus for determining humidity of gases



Sept. 28 1920 I L$L243 J. c. IRWIN, JR

APRARATUS FOR DETERMINING HUMIDITY OF GASES Filed April 27; 1925 INVENTOR.

W ATTORNEY.

NITED STATES JAMES C. IRWIN, JR., OF KANSAS CITY, MISSOURI.

APPARATUS FOR DETERMINING HUMIDITY OF GASES.-

Application filed April 27, 1925. Serial No. 26,313.

My invention relates to improvements in apparatus for determining humidity in gases.

It relates particularly to the determination of humidity in connection with the use of wet and dry bulb thermometers.

One of the objects of my invention is to provide a novel apparatus by which liability of the water freezing by contact with cold gas is eliminated; to ascertain humidity of gases in such confined spaces as it is impracticable with the usual apparatus; to obtain a maximum accuracy of determination; to enable the operator to get the thermometers reading while the apparatus is in operation; and to reduce liability of errors due to the usual handling and delay in making the readings.

A further object of my invention is to provide an apparatus of the kind described, which is simple, cheap, easy to operate, not liable to get out of order, which is durable, and which is eflicient and accurate in operation.

The novel features ofmy invention are hereinafter fully described and claimed.

In the accompanying drawing, which illustrates the preferred embodiment of an apparatus embodying my invention,

Fig. 1 is a longitudinal vertical section of my improved apparatus.

Fig. 2 is a top view, partlybr'oken away, of the same.

Similar reference characters designate similar parts in the different views.

1 designates a casing comprising a horizontal tube having therethrough a longi-' tudinal gas passage, preferably rectangular in cross section, and rovided with a gas inlet 2 at one end, an a gas outlet 3 at the other end. The outlet 3 is enlarged and has mounted in it an electric motor 4 provided with a fan the blades, 6, of which are set so as to force the gas, the humidity of which is to be determined, through the casing 1, to the'right, as viewed in the drawing, and as indicated by the arrows.

In the casing 1 adjacent to the inlet 2 is provided a gas heating means, which is preferably an electric heater, of any usual type suited for the purpose, and which is provided with a tubular insulation body 7, the

'usual resistance wires 8, two binding posts 9, two wires 10 respectively connected to said posts 9, and, outside the casing 1, being mounted in the usual flexible connecting cord 11 having attached-to it an ordinary connecting plug 12 adapted to be inserted 1n any convenient electric light socket. Connected to the motor 4 and to the wires '10 respectively are two wires 13. In this manner the fan motor and the electric heater may be supplied with current from a single socket.

i The heater body 7 may have in it extending from the top and bottom respectively two sets of interlapping bafiies '14 designed to make the gas travel a sinuous course through the heater. Intermediate of. the heater 7 and the outlet 3, the casing '1 may be provided with an upstanding baflle .15.

The casing 1 has in its top an opening normally closed by a removable cover 16, disposed between the heater 7 and the motor 4, and which carries and has extending vertically through it 'two ordinary glass ther-- mometers 17 and 18, the bulbs of 1 which, when. the cover is closed being in the. gas passage, the thermometer 18 being of the ordinary wet bulb type.

The bulbs 19 and 20 of the thermometers 17 and 18 are disposed 'intermediately of the baflie 15 and the motor 4.

To keep the exterior of the bulb 20 wet, it has connected to it a wick 21, which extends into the upper part of a water receptacle 22, which is carried on the under side of the cover 16. The latter is provided with a filling opening communicating with the receptacle 22, said opening being normally closed by a screw plug 23.

The casing 1 may be mounted on a suitable base .24, which may be supported in the chamber, pipe or other receptacle, not shown, which contains the gas to be tested for humidity.

Or the casing 1 may be inserted in a pipe line carrying gas to be tested.

On the outside of the casing 1 may be fastened a thermometer 25, by which the normal temperature of the gas enveloping the casing 1 may be ascertained.

The capacity of the electric heater may be such as to warm the cold gas to a degree at which the wet bulb temperature will be somewhat above thirty two degrees Fahrenheit. This will prevent the water from freezing on the wet bulb. By locating the the motor 4 is operated, by making the proper connection of the plug 12, the gas will enter the casing 1 through the inlet 2 and will pass through the heater body 7 and will be heated by the heat from the wires 8. The heated gas, will pass through the casing, being drawn therethrough by the fan blades 6, and on passing the bulbs 19 and 20, the latter will be heated, the evaporation of the water on the bulb 20, due to the current of warmed gas, causing the thermometer 18 to indicate a lower temperature than the thermometer 17. This difference in indicated temperature will indicate the degree of humidity of the gas which is being tested, the dryer the gas, the greater will be the difference in temperatures indicated by the thermometers 17 and 18, due to the greater evaporating, and therefore, cooling effect of the dryer gas on the wet bulb.

By having the apparatus set under conditions in which the thermometers 17 and 18 can have their graduations visible, the temperatures may be read while the apparatus is in operation, thereby obviating the handling of the thermometers for this purpose, and thus obtaining readings that are without the errors, which occur when the thermometers must be removed from the gas with which they are being employed.

The apparatus may be operated continuously, exceptingat such times as it may be required to add water'to the water receptacle 22. As shown, the wick 21 serves as a siphon, and by lowering its attachment to the bulb 20, most of the water may be withdrawn by it from the receptacle 22 before it is required to fill the latter.

I do not limit my invention to the structure or particular steps described, as modifications, within the scope of the appended claims, may be made without departing from the spirit of my invention.

What I claim is 1. In an apparatus of the kind described, the combination with a casing having a gas passage having an inlet and an outlet, of two thermometers having their bulbs in said passage, means located in said passage for constantly supplying moisture to the bulb of one of said thermometers, means for producing a current of a gas, the humidity of which is to be determined, through said passage and in contact with said bulbs, and means for heating said current of gas prior to the contact of the gas with said bulbs.

2. In an apparatus of the kind described, the combination with a casing having a gas passage provided with an inlet and an out let, of two thermometers having their bulbs in said passage, means located in said passage for constantly supplying moisture to the bulb of one of said thermometers, bafiles in said passage, heating means in said passage between said battles, and means for establishing a current of a gas, the humidity of which is to be determined, through said, passage, first in contact with said heating means and then in contact with said bulbs.

3. In an apparatus of the kind described, the combination with a casing having a gas passage therethrough, and having an opening communicating'with said passage and a cover for said opening, of two thermometers carried by said cover and having their bulbs in said passage when the cover closes said opening, a water receptacle carried by said cover, means for conveying water from said receptacle to one of said bulbs, heating means in said passage, and means for producing and forcing a current of gas, the humidity of which is to be determined, through said passage, first in contact with said heating means and then in contact with said bulbs.

In testimony whereof I have signed my name to this specification.

JAMES C. IRWIN, JR. 

